Preparation method of battery shell, battery and electronic equipment

Abstract

The invention discloses a preparation method of a battery shell, a battery and electronic equipment, the preparation method of the battery shell comprises the following steps: a tubular workpiece is conveyed to a multi-wire cutting unit for cutting to obtain a plurality of shell rough blanks, and the multi-wire cutting unit comprises rotating rollers and cutting wires wound between the rotating rollers; the inner walls and the cutting faces of the multiple shell rough blanks are subjected to surface cleaning, and a semi-finished shell is obtained; cleaning the outer surface of the semi-finished product shell to obtain a finished product battery shell; wherein the battery shell is made of steel, and the cutting line comprises a plurality of diamond wire saws which are arranged on the same plane in parallel. According to the preparation method of the battery shell, the cutting precision can be improved, the cutting efficiency can be greatly improved, and the cost is saved.

Description

Technical Field

[0001] This application relates to the field of battery technology, and in particular to methods for preparing battery casings, batteries, and electronic devices. Background Technology

[0002] Currently, lithium batteries are widely used in mobile phones, laptops, and various electronic devices. Lithium battery testing standards include the strength and compressive strength of the casing, and using steel as the battery casing is a current technological trend. It is well known that steel materials (such as carbon steel and stainless steel) are harder than aluminum. While meeting the structural strength requirements and sufficient mechanical load-bearing capacity of the battery casing, the sidewalls of stainless steel battery casings can be thinner than those of aluminum battery casings. Therefore, stainless steel battery casings can reduce battery weight and also increase the volumetric energy density of the battery.

[0003] In known technologies, steel shell profiles are cut using lasers, and then the battery cells are encapsulated within them. However, because the steel shell material is extremely thin and has a very small heat capacity, laser cutting easily leads to rapid heat accumulation and diffusion, creating a molten surface. This results in poor cut surface quality, requiring subsequent processes (such as end face grinding) to form a smooth end face. Consequently, the steel shell manufacturing process is more complex and costly. Summary of the Invention

[0004] In view of the shortcomings of the prior art, this application provides a method for preparing a battery casing, a battery and electronic equipment, aiming to solve the problem of high cost of laser-cut steel casing batteries.

[0005] To achieve the above objectives, this application proposes a method for preparing a battery casing, comprising the following steps: The tubular workpiece is conveyed to a multi-wire cutting unit for cutting to obtain multiple shell blanks. The multi-wire cutting unit includes rotating rollers and cutting wires wound between the rotating rollers. The inner walls and cut surfaces of the multiple shell blanks are cleaned to obtain semi-finished shells. The outer surface of the semi-finished shells is cleaned to obtain finished battery shells. The battery shells are made of steel, and the cutting wires include multiple diamond wire saws arranged parallel to each other on the same plane.

[0006] In some embodiments, the wall thickness of the tubular workpiece is 100μm to 500μm.

[0007] In some embodiments, the housing is made of stainless steel, and the diameter of the diamond wire saw is smaller than the wall thickness and is selected from 25μm to 350μm.

[0008] In some embodiments, the core material of the diamond wire saw is a composite core formed by twisting two or more piano wires together; and / or, the minimum diameter of the diamond wire saw is 25μm to 60μm, and the maximum diameter of the diamond wire saw is 140μm to 350μm.

[0009] In some embodiments, the bulk density of the diamond abrasive grains in the diamond wire saw is 0.24 g / cm³. 3 ~0.87g / cm 3 The diamond abrasive grains in the diamond wire saw have a particle size Dv50 of 8μm to 40μm.

[0010] In some embodiments, the cutting linear speed is 1 m / s to 8 m / s, and the cutting feed speed is 0.1 mm / min to 2.5 m / min.

[0011] In some embodiments, the multi-wire cutting unit includes a clamping member capable of simultaneously accommodating multiple tubular workpieces, the clamping member being a full-length V-groove clamping member including elastic material clamping blocks.

[0012] In some embodiments, the surface cleaning of the inner walls and cut surfaces of the plurality of shell blanks to obtain a semi-finished shell includes: providing a water jet device, placing the shell blanks in the fixture of the water jet device to position the shell blanks; and controlling the spray gun of the water jet device to align with the inner wall of the shell blanks and perform liquid spraying processing.

[0013] To achieve the above objectives, this application also proposes a battery, including a battery cell and the aforementioned battery casing.

[0014] To achieve the above objectives, this application also proposes an electronic device including the aforementioned battery.

[0015] The beneficial effects of this application are: This application replaces laser cutting with diamond wire saw multi-wire cutting technology as a physical cold working process. Diamond wire sawing cuts through physical grinding, which significantly reduces the heat-affected zone compared to laser cutting. This results in slag-free cuts with relatively smooth surfaces, improving cutting accuracy and eliminating subsequent end-face grinding processes. Furthermore, because multiple cutting stations can be set up simultaneously to cut multiple workpieces at once, processing efficiency is greatly improved. Therefore, the processing cost of battery casings can be significantly reduced. Attached Figure Description

[0016] The embodiments described in this application are not limited to the accompanying drawings, which are only some of the embodiments described herein. Those skilled in the art can obtain drawings of other embodiments based on the content of this application.

[0017] Figure 1 This is a flowchart of a preparation method according to an embodiment of this application; Figure 2 This is a flowchart of a preparation method according to another embodiment of this application.

[0018] The realization of the objective, functional features and advantages of the present invention will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0019] To make the technical solutions and advantages of this application clearer, the application and its beneficial effects will be described in further detail below in conjunction with specific embodiments. The following description is provided to enable those skilled in the art to fully understand this application and is not intended to limit the subject matter recorded in the claims.

[0020] The "range" disclosed in this application is defined by a lower limit and an upper limit. A given range is defined by selecting a lower limit and an upper limit, which define the boundaries of a particular range. Ranges defined in this way can include or exclude endpoints and can be arbitrarily combined; that is, any lower limit can be combined with any upper limit to form a range. For example, if ranges of 60-120 and 80-110 are listed for a specific parameter, it is expected that ranges of 60-110 and 80-120 are also included. Furthermore, if minimum range values ​​of 1 and 2 are listed, and maximum range values ​​of 3, 4, and 5 are listed, then the following ranges are all expected: 1-3, 1-4, 1-5, 2-3, 2-4, and 2-5. In this application, unless otherwise stated, the numerical range "ab" represents a shortened representation of any combination of real numbers between a and b, where a and b are real numbers. For example, the numerical range "0-5" indicates that all real numbers between "0-5" have been listed in this article; "0-5" is simply a shortened representation of these numerical combinations. Furthermore, when a parameter is stated as an integer ≥2, it is equivalent to disclosing that the parameter is, for example, an integer such as 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, etc.

[0021] Unless otherwise specified, all embodiments and optional embodiments of this application can be combined to form new technical solutions.

[0022] Unless otherwise specified, all technical features and optional technical features of this application may be combined to form new technical solutions.

[0023] Unless otherwise specified, all steps in this application may be performed sequentially or randomly, preferably sequentially. For example, the method includes steps (a) and (b), indicating that the method may include steps (a) and (b) performed sequentially, or it may include steps (b) and (a) performed sequentially. For example, the mention that the method may also include step (c) indicates that step (c) may be added to the method in any order. For example, the method may include steps (a), (b), and (c), or it may include steps (a), (c), and (b), or it may include steps (c), (a), and (b), etc.

[0024] Stainless steel is harder than aluminum. While meeting the structural strength requirements of the battery casing and bearing sufficient mechanical load strength, the sidewalls of stainless steel battery casings can be thinner than those of aluminum battery casings. Therefore, stainless steel battery casings can reduce the weight of the battery casing and also increase the volumetric energy density of the battery.

[0025] However, because the stainless steel casing of the steel-cased battery is extremely thin and has a very small heat capacity, it is easy for heat to accumulate and spread rapidly during laser cutting, resulting in a molten surface and thus poor cut surface quality.

[0026] In view of this, refer to Figure 1 This application proposes a method for preparing a battery casing, comprising the following steps: S1: The tubular workpiece is conveyed to the multi-wire cutting unit for cutting to obtain multiple shell blanks. The multi-wire cutting unit includes rotating rollers and cutting wires wound between the rotating rollers. S2: Clean the inner walls and cut surfaces of the multiple shell blanks to obtain semi-finished shells; S3: Clean the outer surface of the semi-finished casing to obtain the finished battery casing.

[0027] The battery casing is made of steel, and the cutting wire includes multiple diamond wire saws arranged in parallel on the same plane.

[0028] In this solution, the diamond wire saw is key to achieving the multi-wire cutting effect. Using diamond as the abrasive surface allows the wire saw to efficiently cut high-hardness stainless steel. Furthermore, the wire saw experiences slow wear and a long lifespan, maintaining processing accuracy over extended periods and ensuring the stability of mass production. Multi-wire cutting relies on the physical grinding of the stainless steel shell by the wire saw and abrasive. Diamond wire saw cutting leaves a purely mechanically machined surface, resulting in better material integrity in the cut area, superior fatigue strength, and corrosion resistance. Compared to laser cutting, it avoids heat input, thus preventing problems such as slag formation, overheating, thermal deformation, and changes in the material's metallographic structure, ensuring that the original strength of the shell material is not compromised during processing.

[0029] In this embodiment, multiple cutting stations can be set up, and each station is equipped with a cutting line, so that multiple tubular workpieces can be simultaneously cut into several shell blanks in one processing stroke. This is not only much more efficient than the sequential processing of laser cutting, but also ensures that the length and cut shape of all blanks have a high degree of consistency, which is suitable for large-scale standardized production of batteries and greatly reduces costs compared to laser cutting.

[0030] In some embodiments, the cut surface of the tubular workpiece can be a rectangle, a circle, or other shapes required for the battery casing; this application does not limit this.

[0031] In some embodiments, the steel may be selected from steel types known to those skilled in the art for preparing steel-cased battery casings, such as carbon steel, stainless steel, etc., as long as they meet the required corrosion resistance, strength and rigidity of the battery. This application does not limit this.

[0032] In some embodiments, a diamond wire saw includes a wire core, a plating layer, and abrasive grains, the abrasive grains being deposited on the plating layer of the wire saw by known methods such as electroplating.

[0033] In some embodiments, the wall thickness of the tubular workpiece is 100 μm to 500 μm.

[0034] When used to cut tubular workpieces with wall thicknesses on the order of micrometers, any uneven stress can easily lead to deformation of the tube wall. Furthermore, at the micrometer scale, even the smallest burrs, chipped edges, or tilted cross-sections are magnified, severely weakening the pressure resistance and sealing performance of the casing, becoming a fatal flaw affecting battery safety. Therefore, the diamond wire saw multi-wire cutting process in this solution can produce smooth, flat cuts with sharp, defect-free edges, achieving the precision cutting requirements needed for electrochemical devices.

[0035] For example, the wall thickness of the tubular workpiece can be 100μm, 120μm, 140μm, 160μm, 180μm, 200μm, 220μm, 240μm, 260μm, 280μm, 300μm, 320μm, 340μm, 360μm, 380μm, 400μm, 420μm, 440μm, 460μm, 480μm, 500μm, or within any two of the above values.

[0036] In some embodiments, the wall thickness of the tubular workpiece is 150 μm.

[0037] In some embodiments, the diameter of the diamond wire saw is smaller than the wall thickness and is selected from 25 μm to 350 μm.

[0038] When the wire diameter is smaller than the wall thickness and falls within the aforementioned range, the stainless steel wire saw can sharply cut into the stainless steel tubular workpiece, and mainly concentrates the force on the cutting area rather than on the entire cross-section of the tubular workpiece, reducing the lateral stress transmitted to the workpiece, thereby effectively protecting the geometry of the extremely thin tube wall and preventing mechanical deformation during the cutting process.

[0039] For ultra-thin-walled tubes of 100μm to 200μm, ultra-fine wire diameters of 25μm to 60μm are preferred, resulting in narrow kerfs and high material utilization. For thicker-walled tubes of 300μm to 500μm, thicker wire diameters of 140μm to 350μm are used to ensure the straightness and efficiency of the cutting.

[0040] For example, the wire diameter of a diamond wire saw can be 25μm, 50μm, 75μm, 100μm, 125μm, 150μm, 175μm, 200μm, 225μm, 250μm, 275μm, 300μm, 325μm, 350μm, or within any two of the above values.

[0041] In some embodiments, the wall thickness of the tubular workpiece is 150 μm, and the wire diameter of the diamond wire saw is preferably 60 μm to 150 μm.

[0042] In some embodiments, the core material of a diamond wire saw is a composite core formed by twisting two or more piano wires together.

[0043] Piano wire is a high-strength material made from carbon alloy steel through lead bath quenching and cold drawing. This material has high tensile strength, excellent elastic limit and fatigue resistance.

[0044] Formed by twisting two or more piano wires together, this wire saw offers superior toughness, flexibility, and fatigue resistance, minimizing lateral compressive stress on the tubing. The twisted structure of the composite core creates chip grooves, enhancing chip space and cooling, resulting in higher cutting speeds. Furthermore, the twisted structure of the two piano wires effectively buffers and absorbs cutting vibrations, significantly improving processing stability, extending the wire saw's lifespan, and directly contributing to better cross-sectional quality.

[0045] In some embodiments, the twist direction can be right-handed or left-handed (S or Z direction), and the twist pitch is 0.5mm to 5.0mm.

[0046] In some embodiments, the core material of a diamond wire saw is a composite core formed by twisting two or three strands of piano wire together.

[0047] In some embodiments, the wall thickness of the tubular workpiece is 150 μm, and the core material of the diamond wire saw is a composite core formed by twisting two strands of piano wire, with a diameter of 15 micrometers.

[0048] In some embodiments, the wall thickness of the tubular workpiece is 150 μm, and the core material of the diamond wire saw is a composite core formed by twisting three strands of piano wire, with the diameter of the piano wire being 10 micrometers.

[0049] In some embodiments, the bulk density of the diamond abrasive grains in the diamond wire saw is 0.24 g / cm³. 3 ~0.87g / cm 3 The particle size Dv50 of the diamond abrasive grains in the diamond wire saw is 8μm to 40μm.

[0050] The lower the abrasive density, the sparser the abrasive grain distribution, the more sufficient the chip space for each abrasive grain, the gentler the cutting force, and the fewer chips produced. This can effectively reduce the plowing and tearing effects on the workpiece material, resulting in a smoother cutting surface and less edge chipping, but the cutting efficiency will be reduced.

[0051] In some embodiments, for extremely thin tubular workpieces of 100μm~200μm, a bulk density of 0.24 g / cm³ is selected. 3 ~0.45 g / cm 3 Low-density abrasive diamond wire saw.

[0052] The higher the abrasive volume density, the denser the abrasive distribution, and the more effective abrasive particles participate in cutting, resulting in higher cutting efficiency, but the cutting surface is not as fine as that of low volume density.

[0053] In some embodiments, for tubular workpieces with a diameter of 300 μm to 500 μm, a density of 0.65 g / cm³ is selected. 3 ~0.87 g / cm 3 High-density abrasive diamond wire saw.

[0054] For example, the bulk density of the diamond abrasive grains in a diamond wire saw can be 0.24 g / cm³. 3 0.34g / cm 3 0.44 g / cm 3 0.54g / cm 3 0.64 g / cm 3 0.74g / cm 3 0.84 g / cm 3 Or it falls within the range of any two of the above values.

[0055] In some embodiments, 8μm to 15μm fine abrasive grains have an extremely shallow cutting depth per grain, making it easy to obtain a smooth cross-section without chipping. 25μm to 40μm particles have a deeper cutting depth per grain, providing higher cutting efficiency when cutting thicker pipes, and the larger chip space prevents the wire saw from clogging.

[0056] For example, the particle size Dv50 of the diamond abrasive grains in a diamond wire saw can be 8μm, 11μm, 14μm, 17μm, 20μm, 23μm, 26μm, 29μm, 32μm, 35μm, 38μm, or within any two of the above values.

[0057] In some embodiments, the particle size Dv50 of the diamond abrasive is preferably 10 μm to 15 μm.

[0058] In some embodiments, the linear velocity of the multi-wire cutting is 1 m / s to 8 m / s, and the feed rate of the multi-wire cutting is 0.1 mm / min to 2.5 m / min.

[0059] Through the precise structural design and coordinated cutting parameters of the diamond wire saw, problems such as expansion of the heated area of ​​the tube due to improper cutting, resulting in severe warping and twisting deformation, are avoided. For ultra-thin stainless steel tubes, a higher linear speed helps with chip removal and cooling, but if it is too high, it will cause workpiece vibration; a lower feed rate can avoid sudden impact forces that could cause a sudden increase in stress and deformation of the tube.

[0060] In some embodiments, a diamond wire saw using a composite core formed by twisting two or more piano wires as a carrier has a wire diameter of 50 μm, an abrasive grain Dv50 of 10 μm, and a bulk density of 0.64 g / cm³. 3 The diamond wire saw is set to a linear speed of 6 m / s after the wire is loaded to provide sufficient cooling and cutting power; while the feed rate is set at 0.15 mm / min to ensure that the cutting force is gentle enough not to cause any deformation.

[0061] For example, the linear velocity of multi-wire cutting can be 1 m / s, 2.5 m / s, 3.0 m / s, 3.5 m / s, 4.0 m / s, 4.5 m / s, 5.0 m / s, 5.5 m / s, 6.0 m / s, 6.5 m / s, 7.0 m / s, 7.5 m / s, 8.0 m / s, or within any range of two of the above values.

[0062] For example, the feed rate can be 0.1 mm / min, 500 mm / min, 0.5 m / min, 1.1 m / min, 1.6 m / min, 2.1 m / min, 2.5 m / min, or within any two of the above values.

[0063] In some embodiments, the multi-wire cutting unit includes a clamping member capable of simultaneously accommodating multiple tubular workpieces, the clamping member being a full-length V-groove clamping member including elastic material clamping blocks.

[0064] Because the tubular workpiece in this application has poor rigidity, the clamping and support of the workpiece during cutting also have a significant impact on the cutting effect. The V-groove provides a stable positioning reference for the tube, and the elastic material clamping block within it evenly distributes the clamping force through its own slight deformation, effectively avoiding indentations on the ultra-thin tube wall caused by point contact or uneven clamping force. The clamping device in this solution can prevent the tubular workpiece from vibrating and being damaged when it is cut into a shell blank.

[0065] In some embodiments, the V-groove may be made of bakelite, aluminum alloy, or rigid plastic.

[0066] In some embodiments, the elastic material includes polymeric materials such as polyurethane and specialty rubber.

[0067] To improve efficiency and stability, multiple stainless steel tubes can be tightly mounted side-by-side in a fixture for simultaneous cutting. Clamping multiple tubes at once increases the overall rigidity of the workpiece, providing mutual support and resulting in a far superior effect compared to single-tube cutting.

[0068] In some embodiments, the number of tubular workpieces is 10 to 20.

[0069] In some embodiments, refer to Figure 2 Step S2 involves surface cleaning of the inner walls and cut surfaces of the multiple shell blanks to obtain a semi-finished shell, comprising: S201: Provide a water jet device, and place the shell blank in the fixture of the water jet device to position the shell blank; S202: Control the spray gun of the water jet device to aim at the inner wall of the shell blank and perform liquid spraying.

[0070] In some embodiments, the jet pressure is in the low to medium pressure range, specifically 20 MPa to 80 MPa. This pressure range is sufficient to overcome the adhesion of contaminants such as metal powder and oil film, effectively peeling and washing them away, but is far below the threshold pressure that causes plastic deformation of the thin-walled steel shell.

[0071] In some embodiments, the spray angle is maintained at an acute angle of 10° to 30° to form a tangential cleaning force. At the same time, the target distance is appropriately increased to 15mm to 30mm so that the jet has a certain degree of diffusion when it contacts the workpiece surface, further reducing the impact pressure per unit area.

[0072] In some embodiments, the spray gun is ensured to move smoothly at a constant speed to avoid lingering in any localized area for too long and to prevent energy buildup.

[0073] This solution utilizes water jet cleaning to effectively remove burrs and achieve a consistent surface finish. The clean, smooth inner surface prevents scratches on the battery separator and electrodes. Cleaning thoroughly removes residual metal particles, polishing media, and various contaminants from previous processes, ensuring a high degree of cleanliness both inside and outside the casing. This prevents any residual conductive particles from causing internal short circuits and leading to battery failure. A proper cleaning method can improve the final product yield.

[0074] In some embodiments, the water jet device also sprays liquid onto the cut surfaces of the housing blank. This helps improve the sealing performance between the housing and the cover plate.

[0075] To address the aforementioned problems, this application also proposes a battery, including a cell and the aforementioned battery casing. A battery includes any device in which an electrochemical reaction occurs to convert chemical energy into electrical energy, and specific, non-limiting examples include all types of primary batteries, secondary batteries, fuel cells, solar cells, or capacitors. In particular, the battery is a lithium secondary battery, including lithium metal secondary batteries, lithium-ion secondary batteries, lithium polymer secondary batteries, or lithium-ion polymer secondary batteries.

[0076] The casing of this application has higher initial strength, fatigue strength, and toughness, enabling it to better withstand the expansion and contraction of the battery cell during charge-discharge cycles, as well as external mechanical shocks and vibrations, thus providing a higher safety margin for the battery. According to some embodiments of this application, regardless of the conventional selection of battery type, as long as the aforementioned casing is included, the claimed beneficial effects can be obtained.

[0077] To address the aforementioned problems, this application also proposes an electronic device including the aforementioned housing.

[0078] According to some embodiments of this application, electronic devices include, but are not limited to, mobile phones, smartphones, laptops, tablets, wearable devices, smartwatches, smart bracelets, smart glasses, power banks, televisions, game consoles, game controllers, digital cameras, smart speakers, headphones, keyboards, mice, monitors, drones, audio equipment, home appliances, toys, power tools, automobiles, motorcycles, electric bicycles, bicycles, robots, robot dogs, industrial robots, and android robots.

[0079] The technical solution of this application will be further described in detail below with reference to specific embodiments.

[0080] Example 1: Twelve 304 stainless steel tubular workpieces with a wall thickness of 300 μm were loaded in parallel into the clamping assembly of a multi-wire cutting machine. The cutting wire of the multi-wire cutting machine was a diamond wire saw with a wire diameter of 115 μm. The wire core of the diamond wire saw was a single piano wire, and the diamond abrasive grains had a particle size (Dv50) of 25 μm and a bulk density of 0.70 g / cm³. 3 ; The cutting machine is started, and with the full cooling and lubrication of the coolant, 6 parallel diamond wire saws simultaneously cut 12 tubular workpieces. The feed rate is 1.5 mm / min and the linear speed is 5.0 m / s, resulting in multiple shell blanks. A high-pressure water jetting device is provided to clamp the shell blanks one by one onto the device's fixture, ensuring accurate positioning and reliable fixation; the device's multi-axis robotic arm is controlled to precisely insert the spray gun into the shell blank; the water jet pressure is set to 50MPa, and the medium is deionized water mixed with a trace amount of neutral cleaning agent (sodium bicarbonate); the device is started, and while the spray gun moves at a constant speed along the shell axis, the shell rotates at a constant speed under the drive of the fixture, so that the jet performs a scanning cleaning of the inner wall in a spiral trajectory, the spray angle is maintained at 20°, and the target distance is controlled at 20mm; Finally, the shells undergo alkaline ultrasonic cleaning and two rounds of deionized water ultrasonic rinsing in a multi-tank ultrasonic cleaner, and are then dried in a clean hot nitrogen atmosphere at 80°C to ensure that no contaminants remain on the shell surface, resulting in multiple shells.

[0081] Example 2: The tubular workpiece has a wall thickness of 150 μm, is cut with a diamond wire saw with a wire diameter of 50 μm, has a diamond abrasive grain size (Dv50) of 10 μm, and a bulk density of 0.35 g / cm³. 3 The linear velocity is 2.5 m / s, the feed rate is 0.1 mm / min, and the rest are the same as in Example 1.

[0082] Example 3: The bulk density of diamond abrasive grains is 0.24 g / cm³. 3 For the rest, please refer to Example 1.

[0083] Example 4: The diamond wire saw has a wire diameter of 77 μm, and the rest is as described in Example 1.

[0084] Example 5: The diamond wire saw has a wire diameter of 25 μm, and the rest is as described in Example 1.

[0085] Example 6: The diamond abrasive grains have a particle size Dv50 of 8 μm and a cutting linear velocity of 6 m / s. For other details, refer to Example 1.

[0086] Example 7: The core of the diamond wire saw is two strands of piano wire with a twist pitch of 1mm. For other details, refer to Example 1.

[0087] Example 8: The tubular workpiece has a wall thickness of 500 μm, and the cutting wire is a diamond wire saw with a wire diameter of 290 μm. Other details are as described in Example 1.

[0088] Example 8: The tubular workpiece has a wall thickness of 300 μm, and the cutting wire is a diamond wire saw with a wire diameter of 115 μm. Other details are as described in Example 1.

[0089] Example 9: The tubular workpiece has a wall thickness of 300μm, the cutting wire is a diamond wire saw with a wire diameter of 115μm, the cutting speed is 6m / s, and the feed rate is 1m / min. Other details are as described in Example 1.

[0090] Example 10: The tubular workpiece has a wall thickness of 300μm, the cutting wire is a diamond wire saw with a wire diameter of 115μm, the cutting speed is 8m / s, and the feed rate is 2m / min. Other details are as described in Example 1.

[0091] Comparative Example 1: The single tubular workpiece from Example 1 was loaded into the chuck of the laser cutting machine. Using a 1000W fiber laser cutting machine, with the laser power set to 300W, the cutting speed to 1.5 m / min, the auxiliary gas to be high-purity nitrogen (purity ≥99.999%), and the nitrogen pressure to be 1.8 MPa, the laser cutting program was started. The laser beam and the high-pressure nitrogen acted simultaneously on the workpiece to cut it, resulting in a shell.

[0092] Performance testing 1. Dimensional compliance rate Three hundred shells were randomly selected from the same production batch of the examples and comparative examples as samples. These shell samples were fixed in the fixture of a high-precision coordinate measuring machine (CMM) to ensure no deformation and accurate positioning. In the control software, the following items were measured programmatically for each shell: Outer diameter: At least three cross-sections were selected 5mm below the shell opening, with four points measured at each cross-section, and the average value was taken. Length: The vertical distance between the two end faces of the shell was measured at at least four points evenly distributed around the circumference, and the average value was taken. Wall thickness at the opening: At the opening cross-section, the wall thickness data was obtained at at least eight evenly distributed points using the CMM's cross-section scanning function or point measurement. Each measured value was compared with the tolerance requirements on the design drawings, the number of qualified items for each dimension was counted, and the pass rate was calculated.

[0093] 2. Cross-sectional surface roughness Fix the housing to the contact surface profilometer, ensuring the cut surface is perpendicular to the probe's movement direction. On the cut surface, select at least three evenly distributed measurement positions. At each position, scan with the probe perpendicular to the cutting pattern direction. The evaluation length (ln) should include at least five sampling lengths (lr). The instrument automatically calculates and outputs the arithmetic mean deviation Ra.

[0094] 3. Shell seal yield pressure One end of the shell is laser-sealed to a cover plate of the same material to simulate the state of a real battery. The welded sample is then installed on a pressure burst tester to ensure there is no leakage at the connection. Water is used as the pressure transmitting medium and pressurized at 0.1 MPa / s. The pressure-time curve is monitored and recorded in real time. When the curve first shows a significant nonlinear deviation or pressure plateau, the pressure value at that moment is recorded, which is the sealing yield pressure.

[0095] 4. Simulated fatigue strength test Similar to test 3, one end of the casing is sealed and welded to the cover plate. The sample is installed on a pulse fatigue testing machine and connected to a servo control system that can generate alternating pressure. The test pressure range is set as follows: the minimum pressure is set to 0.1 MPa to simulate the static state, and the maximum pressure is set to 40% of the sealing yield pressure. The internal pressure of the battery cell after full charge expansion is simulated cyclically. To avoid resonance and thermal effects, the frequency is set to 2 Hz. The testing machine is started, and the system automatically pressurizes and depressurizes the inner cavity of the casing cyclically within the set pressure range. The preset number of battery cycles is simulated, and the target number of cycles is set to 1000. If more than 90% of the examples or comparative samples pass 1000 cycles, it is considered excellent; if it is between 80% and 90%, it is considered good; and if it is less than 80%, it is considered unqualified.

[0096] The variable statistics of the examples and comparative examples, as well as the above performance test results, are shown in Table 1 below.

[0097] Table 1. Comparison of parameters and performance between the examples and comparative examples The above performance results demonstrate that, based on comprehensive analysis, all embodiments employing the diamond wire saw multi-wire cutting process significantly outperform the comparative traditional laser cutting in key performance indicators. Embodiment 7 achieved optimal performance in dimensional compliance rate, sealing yield pressure, and fatigue strength. Embodiment 3, by reducing abrasive density, or Embodiment 6, by reducing abrasive particle size, achieved a smooth cut surface with extremely low Ra values. It is noteworthy that poor matching between wire diameter and wall thickness leads to a decrease in surface quality and fatigue performance. However, embodiments with different wall thicknesses of 150 / 300 / 500 μm achieved fatigue pass rates exceeding 88% through synergistic optimization of various parameters. This fully verifies that this technology, through precise parameter control, can stably fabricate ultra-thin stainless steel battery casings with high precision, smooth surfaces, and reliable structures while avoiding thermal damage.

[0098] Furthermore, this solution enables the simultaneous cutting of multiple tubular workpieces. Within the same single processing cycle, its output is far higher than that of the single-piece processing method in Comparative Example 1. Under this premise, the yield is also significantly better than that of laser cutting, demonstrating a huge advantage.

[0099] Without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of the different embodiments or examples.

[0100] The above description is only a part or preferred embodiment of this application and should not be construed as limiting the scope of protection of this application. All equivalent structural transformations made using the content of this application specification under the overall concept of this application, or direct / indirect applications in other related technical fields, are included within the scope of protection of this application.

Claims

1. A method for preparing a battery casing, characterized in that, Includes the following steps: The tubular workpiece is fed to a multi-wire cutting unit for cutting to obtain multiple shell blanks. The multi-wire cutting unit includes rotating rollers and cutting wires wound between the rotating rollers. The inner walls and cut surfaces of the multiple shell blanks are cleaned to obtain semi-finished shells; The outer surface of the semi-finished battery casing is cleaned to obtain the finished battery casing; The battery casing is made of steel, and the cutting wire includes multiple diamond wire saws arranged in parallel on the same plane.

2. The method for preparing the battery casing according to claim 1, characterized in that, The wall thickness of the tubular workpiece is 100μm~500μm.

3. The method for preparing the battery casing according to claim 2, characterized in that, The shell is made of stainless steel, and the diameter of the diamond wire saw is smaller than the wall thickness and is selected from 25μm to 350μm.

4. The method for preparing the battery casing according to claim 3, characterized in that, The core material of the diamond wire saw is a composite core formed by twisting two or more piano wires together.

5. The method for preparing the battery casing according to claim 3, characterized in that, The bulk density of the diamond abrasive grains in the diamond wire saw is 0.24 g / cm³. 3 ~0.87g / cm 3 ; And / or, the particle size Dv50 of the diamond abrasive grains in the diamond wire saw is 8μm to 40μm.

6. The method for preparing the battery casing according to any one of claims 1 to 5, characterized in that, The cutting linear velocity is 1 m / s to 8 m / s, and the cutting feed rate is 0.1 mm / min to 2.5 m / min.

7. The method for preparing the battery casing according to claim 1, characterized in that, The multi-wire cutting unit includes a clamping member that can simultaneously accommodate multiple tubular workpieces. The clamping member is a full-length V-shaped groove clamping member that includes elastic material clamping blocks.

8. The method for preparing the battery casing according to claim 7, characterized in that, The process of cleaning the inner walls and cut surfaces of the plurality of shell blanks to obtain semi-finished shells includes: A water jet device is provided, and the shell blank is placed in the fixture of the water jet device to position the shell blank; The water jet device is controlled to spray liquid onto the inner wall and cut surface of the shell blank.

9. A battery, characterized in that, Includes the battery cell and the battery casing as described in any one of claims 1 to 8.

10. An electronic device, characterized in that, Includes the battery as described in claim 9.

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